New Process to make non nucleosidal reverse transcriptase inhibitors (NNRTI) for the treatment of HIV

ABSTRACT

A chemical process that can form pharmaceutically acceptable medicaments NNRTI&#39;s for the treatment of HIV starting from thiotriazole compounds. The chemical process can form thiotetrazoles such as 2-((1-(naphthalen-1-yl)-1H-tetrazol-5-yl) thio)-N-(2-nitrophenyl)actetamide that is, a potent NNRTI with nanomolar activity.

The present invention is a new process to synthesize thiotetrazoles that can be used as non nucleosidal reverse transcriptase inhibitors (NNRTI's). The pharmaceutical acceptable salts of the thiotetrazole NNRTI's can be used for the treatment of human immunodeficiency virus (HIV) infection and for the prevention of HIV, in addition as a compliment with other therapies and medicaments used to treat HIV. It is known that compounds that inhibit the function of the HIV Reverse Transcriptase (HIV-RT) can inhibit the replication of the HIV virus in infected cells. Therefore, compounds that can inhibit HIV-RT can be useful for the treatment of HIV and be used for the prevention of contracting HIV. The thiotetrazole analogues made from the process have been shown to have nanomolar activity against HIV. In addition, thiotetrazoles and their pharmaceutical acceptable salts have been proposed to be useful molecules for the deVelopment of medicaments that can be used for the treatment of inflammatory arthritis and hyperuricemia. The thiotetrazoles and their pharmaceutical acceptable salts can also be used as research tools to develop new and/or improve current medicaments for the treatment of life altering diseases such as HIV, inflammatory arthritis, and hyperuricaemia.

The process involves the use of thiotriazoles to make a thiotetrazole anion that is trapped in situ by a suitable electrophile to form a thiotetrazole compound. Thiotriazoles are useful molecules and are used as the starting materials in this process because of their stability and safety associated with their use and storage. The thiotriazoles are converted to thiotetrazoles that can be combined with a suitable electrophile to form a molecule that can have therapeutic properties and/or can be used as a research tool to discover new medicaments in the areas of HIV infection and prophylaxis and/or inflammatory arthritis and hyperuricemia.

In one embodiment of the present invention, the process involves a solvent such as berzene, a substituted thiotriazole 1, a base, and an electrophile that is trapped when the thiolate anion 2 is formed (Scheme 1). The thiotriazole is stirred in benzene at 60° C. in the presence of triethyl amine for at least 1 h and the electrophile is added and stirred for at least 1-24 hours at 60° C. The reaction is monitored using thin layer chromatography (TLC) or other analytical techniques. When the reaction is complete, the reaction has the solvent removed and is purified using crystallization and/or silica gel chromatography to provide the product 2-((1-(naphthalen-1-yl)-1H-tetrazol-5-yl) thio)-N-(2-nitrophenyl)actetamide in 45% yield which has been shown to be a potent NNRTI with nanomolar activity against the wild type and mutated strains of HIV-1

In a second embodiment of the present invention, the process can use different bromide electrophiles and different thiotriazoles to make different NNRTI analogues that can be used as pharmaceutical preparations to treat HIV which causes Acquired Immunodeficiency Syndrome (AIDS).

In a third embodiment of the present invention is that the process has several advantages over other reported processes. For example, current processes to make thiotetrazole analogues use azides under high temperatures which can be explosive and isothiocyanates which are dangerous mutagens. This process is advantageous because it does not use these azides or

For example, 2-((1-(naphthalen-1-yl)-1H-tetrazol-5-yl)thio)-N-(2-nitrophenyl)actetamide, compound 3 (Scheme 1), can be made by stirring in a batch flask by adding to a stirred solution of the thiatriazole 1 (50.0 mg, 0.219 mmol) in benzene (2.19 mL) and added triethylamine (40.0 μL, 0.262 mmol) forming a light yellow mixture. The reaction is then stirred for 18 h and then the bromide (56.0 mg, 0.219 mmol) was added and stirred for an additional 12 h. The reaction progress was monitored using thin layer chromatography and upon completion the reaction was quenched with water (20 mL), and extracted with dichloromethane (3×25 mL) and the organic layer dried over Na₂SO₄, filtered and evaporated in vacuo. The crude residue was purified using column chromatography (ethyl acetate in hexanes) to afford the pure product as a light yellow oil (25.0 mg, 45%). IR (Thin film CHCl₃): 3322, 3066, 2924, 2355, 2325, 1701, 1604, 1585, 1498, 1434, 1396, 1341, 1275, 1242, 1149, 1088, 958, 913 cm⁻¹. ¹H NMR (400 MHz, CDCl₃): 11.0 (1H, s, broad), 8.70 (1H, dd, J=8.0, 1.0 Hz), 8.41 (1H, dd, J=8.0, 1.0 Hz), 8.15 (1H, m), 8.01 (1H, dd, J=8.0, 1.0 Hz), 7.54-7.52 (5H, m), 7.47 (1H, d, J=8.0 Hz), 7.42 (1H, m), 4.28 (2H, s) ppm. ¹³CNMR (400 MHz CDCl₆): 165.6, 156.1, 155.4, 136.0, 134.5, 134.0, 132.2, 129.0, 128.8, 128.7, 127.8, 126.0, 125.3, 124.4, 122.8, 128.8, 128.7, 122.0, 37.4 ppm. MS (EI) m/e (rel intensity): 407 (100), 243 (3), 230 (2), 213 (5), 211 (2), 186 (1), 169 (11), 139 (3) 113 (1) C₁₉H₁₅N₅O₃S. HRMS (EI) m/e C₁₉H,₅N₅O₃S calc'd mass=407.0926, found=407.0920. Further, Thiotetrazole 1 can be made according to the following procedure. For example, N-(Naphthalen-1-yl)-1,2,3,4-thiatriazol-5-amine 1 was made using the general method for thiatriazole synthesis and the crude residue was purified using silica gel chromatography (10-30% ethyl acetate in hexanes) affording the pure thiatriazole 1 as a light tan solid (1.20 g, 75%, mp=122° C.). IR (Thin film CHCl₃): 3391, 3046, 2986, 1550, 1499, 1470, 1424, 1351, 1263, 1220, 1155, 1118, 1050, 894, 741, 703 cm⁻¹. ¹H NMR (400 MHz, CDCl₃): 11.2 (1H, s, broad), 8.12 (1H, m), 8.04 (1H, dd, J=7.5, 1.0 Hz), 7.99 (1H, m), 7.84 (1H, d, J=7.5 Hz), 7.64-7.56 (3H, m) ppm. ¹³C NMR (400 MHz, DMSO-d6): 177.5, 136.6, 134.6, 129.1, 127.3, 127.3, 127.0, 126.6, 126.6, 122.4, 119.1 ppm. MS (EI) m/e (rel intensity): 228 (4), 187 (6), 185 (100), 169 (12), 158 (17), 153 (26), 141 (22), 127 (86), 92 (6), 75 (5), 62 (2). HRMS (EI) m/e C₁₁H₈N₄S calc'd mass=228.0470, found=228.0475.

Thiol 2 was made using the following procedure. To make 1-(Naphthalen-1-yl)-1H-tetrazole-5-thiol 2, a stirred 50° C. solution of the napthyl triazole 1 (50.0 mg, 0.219 mmol) in benzene (2.19 mL) was added triethylamine (39.0 μL, 0.285 mmol). The reaction was stirred at 50° C. for 22 h and the quenched with water (25.0 mL) and ethyl acetate (50.0 mL), washed with 1M HCl (3×20 mL), water (3×20 mL) and brine (3×20 mL). The organic phase was dried over sodium sulfate and evaporated in vacuo to afford 2 as white light pink crystals (70.0 mg, 100% yield, mp=120-122° C.). IR (Thin film CHCl₃): 3046, 2986, 1499, 1470, 1424, 1351, 1263, 1220, 1155, 1118, 1050, 894, 741, 703 cm⁻¹. ¹H NMR (400 MHz, DMSO-d⁶): 8.21 (1H, d, J=8.0 Hz), 8.01 (1H, d, J=8.0 hz), 7.79-7.55 (4H, m) 7.39 (1H, d, J=8.5 Hz) ppm. ¹³C NMR (400 MHz, DMSO-d₆): 134.6, 132.0, 129.6, 129.0, 128.8, 128.3, 127.4, 126.4, 125.3, 122.2 ppm (missing 1 carbon). MS (ESI+) m/e (rel intensity): 229 (90), 228 (4), 227 (2), 217 (3), 213 (2), 212 (14), 204 (3), 201 (100), 200 (5), 197 (4),187 (4), 186 (6), 185 (2). HRMS (ESI) m/e C₁₁H₉N₄S calc'd mass=229.05479, found=229.05525.

The 2-Bromo-N-(2-nitrophenyl)acetamide 4, was made by adding to a stirred solution of o-nitro aniline (462.0 g, 2.52 mmol) in chloroform (25.0 mL) was added bromo acetyl bromide (242.0 μL, 2.77 mmol) dropwise forming a yellow precipitate. The reaction was stirred at room terhperature for 12 h, then quenched with water (75 mL) and extracted with dichloromethane (3×50 mL). The organic washings were dried with sodium sulfate, filtered and evaporated in vacuo to afford a light brown solid (391.0 mg, 51%). In the case that full consumption of the aniline was not achieved, the crude material was reacted again with bromo-acetyl bromide allowing for complete conversion of nitro aniline into the amide product. In this case purification was not necessary because of the high purity obtained and the quantitative yield with respect to the nitro aniline. ¹H NMR (400 MHz, Toluene-d₈): 11.2 (1H, s, broad), 8,74 (1H, d, J=8.0 Hz), 8.26 (1H, d, J=8.0 Hz), 7.71 (1H, t, J=8.0 Hz), 7.27 (1H, t, J=8.0 Hz) ppm. ¹³C NMR (400 MHz, CDCl₃): 165.1, 136.1, 134.0, 126.1, 124.4, 122.2, 29.6 ppm.

The NNRTI 3, has been found to have nanomolar activity against the wild type strains of HIV. In a fourth embodiment of the present invention, the process is also useful for other bromides, R-Br,

R=o-nitro phenyl acetamide

m-nitro phenyl acetamide

p-nitro phenyl acetamide

o-methyl phenyl acetamide

m-methyl phenyl acetamide

p-methyl phenyl acetamide

o-chloro phenyl acetamide

m-chloro phenyl acetamide

p-chloro phenyl acetamide

In a fifth embodiment of the present invention, the process can use other suitable thiotriazoles that have an alkyl, or aryl, or heteroaryl group attached at the C1 position of the thiotriazole ring. 

1. A chemical process that uses a solvent, thiotriazole, a base and a suitable electrophile to form thiotetrazole pharmaceutical compounds for the treatment of infection caused by the human immunodeficiency virus (HIV) and for the treatment of hyperuricaemia.
 2. The process in claim 1 can form thiotetrazole pharmaceutical compounds that are non-nucleosidal reverse transcriptase inhibitors (NNRTI).
 3. The process in claim 1 can form thiotetrazole pharmaceutical compounds that can treat hyperuricaemia.
 4. The process in claim 1 uses an electrocyclization reaction that forms a thiolate that is trapped by the electrophile in situ.
 5. The process in claim 1 can be carried out in 1 step starting with the corresponding thiotriazole.
 6. The process in claim 1 can be carried out in 2 steps starting with the corresponding thiotriazole.
 7. The solvent in claim 1 can be benzene.
 8. The thiotetrazole in claim 1 can be a naphthalene derived thiotetrazole or other C1 functionalized thiotetrazole that is suitable.
 9. The base in claim 1 can be triethyl amine.
 10. The process in claim 1 is heated to at least 50° C.
 11. The process in claim 1 can form pharmaceutical compounds that are non-nucleosidal reverse transcriptase inhibitors (NNRTI) that have inhibitory concentrations in the range of gram (g) to femtomolar (fm).
 12. The process in claim 1 forms pharmaceutical compounds that are non-nucleosidal reverse transcriptase inhibitors (NNRTI) in chemical yields that range from 0.0001%-99.99%.
 13. The process in claim 1 can be performed in a batch vessel that can be sealed.
 14. The batch vessel in claim 13 can hold an inert atmosphere.
 15. The inert atmosphere in claim 13 can be any noble gas.
 16. The reaction vessel in claim 1 can be a microreactor and/or flow apparatus bearing a design engineering functionality consisting of pre-fabricated channels and/or grooves with dimensions ranging from 1 nanometer to 200 micrometers but not limited to these dimensions.
 17. The reaction vessel in claim 16 can have the chemical reaction solvent or fluid passing inside the inner channels and/or grooves with distances travelled by the reaction fluid ranging from 1 fm to 1000 meters but not limited to these dimensions.
 18. The reaction vessel in claim 16 is capable of obtaining temperature ranges from 150° C. to 400° C. but not limited to these temperature ranges.
 19. The reaction vessel in claim 16 is capable of altering and/or regulating the rate of reaction fluid flow and the residence times within the prefabricated channels and/or grooves.
 20. The reaction fluid flow in claim 19 can be within the ranges of 0.0001 mL/minute-500 L/min but not limited to these ranges.
 21. The reaction fluid flow residence times in claim 19 can be within the ranges of 0.00001 seconds-100 hours but not limited to these time ranges.
 22. The thiotetrazoles and their pharmaceutically acceptable salts made in the process of claim 1 can be used as pharmaceutical preparations and therapeutics for the treatment of HIV infections.
 23. The thiotetrazoles and their pharmaceutically acceptable salts made in the process of claim 1 can be used as pharmaceutical preparations and therapeutics for the prevention of HIV infections.
 24. The thiotetrazoles and their pharmaceutically acceptable salts made in the process of claim 1 can be used as pharmaceutical preparations and therapeutics for the treatment of hyperuricaemia.
 25. The thiotetrazoles and their pharmaceutically acceptable salts made in the process of claim 1 can be effective against wild type strains of HIV.
 26. The thiotetrazoles and their pharmaceutically acceptable salts made in the process of claim 1 can be effective against mutated strains of HIV.
 27. The NNRTI made in the process of claim 1 can be used as pharmaceutical preparations and therapeutics for the treatment of wild type and mutant forms of HIV.
 28. The process in claim 1 can form thiotetrazoles in at least 1% yield.
 29. The process in claim 1 can form thiotetrazoles in at least 9% yield.
 30. The process in claim 1 can form thiotetrazoles in at least 19% yield.
 31. The process in claim 1 can form thiotetrazoles in at least 29% yield.
 32. The process in claim 1 can form thiotetrazoles in at least 39% yield.
 33. The process in claim 1 can form thiotetrazoles in at least 49% yield.
 34. The process in claim 1 can form thiotetrazoles in at least 59% yield.
 35. The process in claim 1 can form thiotetrazoles in at least 69% yield.
 36. The process in claim 1 can form thiotetrazoles in at least 79% yield.
 37. The process in claim 1 can form thiotetrazoles in at least 89% yield.
 38. The process in claim 1 can form thiotetrazoles in at least 99% yield.
 39. The process in claim 1 can use bromide elecrophiles (R-Br), where R=o-nitro phenyl acetamide, m-nitro phenyl acetamide, p-nitro phenyl acetamide, o-methyl phenyl acetamide, m-methyl phenyl acetamide, p-methyl phenyl acetamide, o-chloro phenyl acetamide, m-chloro phenyl acetamide, p-chloro phenyl acetamide. 